1. Field of the Invention
The present invention relates to a positioning device for a dental implant, and especially to a positioning device for conveniently making a resin guide bridge and accurately positioning a dental implant in a dental model and a jaw bone in a patient's mouth.
2. Description of the Related Art
Making an artificial tooth in place of a person's damaged tooth is a conventional treatment. However, the conventional treatment has following disadvantages:
1. When a single damaged tooth is extracted and replaced with an artificial tooth, grinding the adjacent natural teeth is necessary so the ground teeth may be used as two supports to hold the artificial tooth. However, the adjacent natural teeth are injured when ground. To avoid the injury to the adjacent natural teeth, a denture may be fixed by metal clasps hooking the adjacent teeth. However, the exposed metal clasps may disfigure the appearance of the teeth.
2. When multiple damaged teeth are replaced with a denture having multiple artificial teeth, few remaining natural teeth support the denture. These remaining natural teeth are pressed strongly when a user chews food and grits the teeth and therefore injure the gums and periodontal tissue.
To avoid the disadvantages of the conventional dental treatment, dental implantation is used to substitute for the treatment. With reference FIGS. 22 and 31, a method of dental implantation is drilling a bone cavity (623A) in an edentulous place of the jaw bone (6A) out of which a damaged tooth removed in a patient's mouth by drilling the edentulous place of the jaw bone (6A). Next, a dental implant (64A) made of titanium is inserted into the bone cavity (623A) and the wound of the bone cavity (623A) in the jaw bone is sutured. After the fixture is integrated, an abutment (65A) screwed on the dental implant (64A) and then a crown (66A) put on the abutment (65A). Since the dental implant (64A) and the abutment (65A) support the crown (66A), the crown (66A) can sustain the force of occlusion.
The depth for which the dental implant (64A) is inserted into the jaw bone and the position in which the dental implant (64A) is located is critical to succeed in the fixed dental implantation. The correct arrangement of the dental implant (64A) is not only the position but also the angulation of the bone cavity (623A) opposite to the upper tooth or the lower tooth so a top (661A) of the crown (66A) fits the corresponding tooth. If the position or the angulation of the bone cavity (623A) is inaccurate, the crown (66A) will not fit the corresponding tooth.
The bone cavity must precisely correspond to the dental implant. When the bone cavity is too small, the dental implant cannot be inserted into the bone cavity. When the bone cavity is overlarge, the dental implant cannot be positioned securely in the bone cavity. Therefore, a multiple sets of drills and resin guide bridges are used to enlarge the bone cavity step by step.
With reference to FIGS. 23 to 25 and 29, a dentist drills a first hole (62) in an edentulous place of a dental model (6) and inserts a first post (7) into the first hole (62). Wax or gypsum is filled in the gap of the teeth to block out the undercut. Then resin is coated on the edentulous place (61) and covers teeth adjacent to the edentulous place (61) to form a first resin guide bridge (8) with a first through hole (81). After the resin hardens, the dentist replaces the first post (7) with a first guide tube (9). The first guide tube (9) is longer than the through hole (81). A diameter of the first guide tube (9) corresponds to a diameter of a first drill bit (101) of a drilling device (10).
With reference to FIGS. 26 to 28, the dentist drills a hole (62) again to enlarge the first hole (62) in sequent to form a fourth hole (623) and manufactures a fourth resin guide bridge (8C) to obtain the multiple sets of the resin guide bridge (8, 8C) and guide tube (9, 93).
With reference to FIGS. 29 and 30, the dentist puts the first resin guide bridge (8) with the first guide tube (9) on an edentulous place (61A) and adjacent teeth on a patient's jaw bone (6A). Because an inner surface of the first resin guide bridge (9) corresponds to the edentulous place (61A) and the adjacent teeth, the first guide tube (9) is precisely located in a point which will be drilled to form a bone cavity (62) later. The dentist then drills the first bone cavity (62A) by the drilling device (10) with the first drill bit (101). Then the dentist takes away the first resin guide bridge (9) and puts a second resin guide bridge to enlarge the bone cavity with a second drill bit. A fourth resin guide bridge (8C) is put on the edentulous place (61A) and the teeth on the patient's jaw bone (6A) to drill a fourth bone cavity (623A) by a fourth drill bit (104) through a fourth guide tube (93), so the dental implant can be inserted into the bone cavity.
However, the above method for implanting the dental implant has following disadvantages:
1. A drill bit of a drilling device must move over the bridge to follow the guide tube so that the patient needs to open mouth wider. A patient with a small mouth or having a damaged tooth in the posterior area suffers greatly from excessively opening his mouth to place the drilling device into the mouth.
2. The dentist needs to stop drilling the bone cavity to measure the depth of the bone cavity.
3. Manufacture of the resin guide bridge is complex because the dentist needs to repeatedly drill the hole and insert the different size of the posts into the holes to manufacture the resin guide bridge.
4. Lacks of outer irrigation may cause the temperature elevated, thus impacted the osteointegration of the implant.